This invention relates to an aerodynamic windshield to door frame interface on a mobile ground vehicle, such as a medium or heavy duty highway truck. More specifically, the interface including the windshield and front door frame, sometimes referred to as the "A" pillar, contains a third order mathematical ellipse when viewed from the top of the vehicle. The inclusion of the third order ellipse in the "A" pillar and in some cases the outer edge of the windshield moves the rear point of tangency further back along the vehicle cab.